• Journal of the Korean Society of Food Science and Nutrition
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• v.24 no.6
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• pp.859-866
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• 1995

This study was done to investigate the effects of chronic ethanol feeding on hepatic microsomal cytochrome system, lipid peroxidation and peroxide metabolizing enzyme activities in 2-acetylaminofluorene(2-AAF) treated rats. Male Sprague-Dawley rats, weighing 120~125g, were pair-fed liquid diets containing 35% of total calories either as ethanol or isocaloric carbohydrates for 6 weeks. After 4 weeks of experimental diet feeding, 2-AAF(100mg/kg body weight) was injected twice a week intraperitoneally. Both weight and percent liver weight per body weight were significantly changed by ethanol feeding. Hepatic microsomal lipid peroxide value and the activities of glutathione(GSH) peroxidase and GSH reductase were not changed by either ethanol or 2-AAF treatment. However the analysis of cytochrome systems showed that both ethanol and 2-AAF increased cytochrome P-450 and bs contents although cytochrome P-450 content was moe affected by 2-AAF while cytochrome b5 content by ethanol. Cytosolic GSH S-transferase activity, which is often elevated during chemical carcinogenesis, also significantly increased by either ethanol feeding or 2-AAF treatment. Overall values for the cytochrome contents and GSH S-transferase activities were highest in 2-AAF treated rats fed ethanol. These results might support the hypothesis that the increase in liver cancer risk associated with chronic ethanol consumption might be due to, at least in part, enhancement of carcinogen bioactivation by ethanol.

• Bulletin of the Korean Chemical Society
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• v.31 no.9
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• pp.2497-2502
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• 2010

Arg13 is a conserved active-site residue in all known Pi class glutathione S-transferases (GSTs) and in most Alpha class GSTs. To evaluate its contribution to substrate binding and catalysis of this residue, three mutants (R13A, R13K, and R13L) were expressed in Escherichia coli and purified by GSH affinity chromatography. The substitutions of Arg13 significantly affected GSH-conjugation activity, while scarcely affecting glutathione peroxidase or steroid isomerase activities. Mutation of Arg13 into Ala largely reduced the GSH-conjugation activity by approximately 85 - 95%, whereas substitutions by Lys and Leu barely affected activity. These results suggest that, in the GSH-conjugation activity of hGST P1-1, the contribution of Arg13 toward catalytic activity is highly dependent on substrate specificities and the size of the side chain at position 13. From the kinetic parameters, introduction of larger side chains at position 13 results in stronger affinity (Leu > Lys, Arg > Ala) towards GSH. The substitutions of Arg13 with alanine and leucine significantly affected $k_{cat}$, whereas substitution with Lys was similar to that of the wild type, indicating the significance of a positively charged residue at position 13. From the plots of log ($k_{cat}/{K_m}^{CDNB}$) against pH, the $pK_a$ values of the thiol group of GSH bound in R13A, R13K, and R13L were estimated to be 1.8, 1.4, and 1.8 pK units higher than the $pK_a$ value of the wild-type enzyme, demonstrating the contribution of the Arg13 guanidinium group to the electrostatic field in the active site. From these results, we suggest that contribution of Arg13 in substrate binding is highly dependent on the nature of the electrophilic substrates, while in the catalytic mechanism, it stabilizes the GSH thiolate through hydrogen bonding.

• Korean Journal of Acupuncture
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• v.18 no.1
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• pp.1-9
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• 2001

Artemisia asiatica Nakai aqua-acupuncture solution (ANAS) was administered once daily for 10 days before the tumor implantation ($1{\times}10^6\;cells$). Body weight, spleen weight and the number of ascitic tumor cells were measured at 6 days after tumor implantation. The change of body weight and the survival rate of mice were observed for 21 days. It was used three biomarkers (quinone reductase, glutathione, glutathione S-transferase) to test chemopreventive potentials of ANAS. ANAS exerted antitumor activity by inhibiting the growth of Ehrlich ascites tumor cells in vivo. Mice given Ehrlich cells and ANAS at $CV_{12}$ and $BL_{18}$ had 57.1% to 49.2% survival after 21 days. Quinone reductase activity and glutathione levels were increased with ANAS. However, glutathione S-transferase level was 1.1-fold with ANAS. These results suggest that ANAS has chemopreventive potential by inducing QR activity and increasing GSH level.

• Toxicological Research
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• v.14 no.2
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• pp.177-181
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• 1998

Dithiocarbamate and mixed disulfide containing allyl functions were designed and synthesized as putative chemopreventive agents, i.e. N,N-diallyldithiocarbamate (DATC) and S-(N,N-diallyldithiocarbamoyl)-N-acetylcysteine (AC-DATC). DATC and AC-DATC were administered and the activities of cytosolic glutathione S-transferase (GST), glutathione reductase (GR) and microsomal N-nitrosodiethylamine (NDEA) deethylase were assayed in order to test the effects of these organosulfur com-pounds on the detoxification and metabolic activation system of NDEA. The amounts of hepatic glutathione (GSH and GSSG) was also determined. The administration of DATC to rats led to an increase in the activity of GR and to an inhibition of CYP2E1-mediated NDEA deethylation. AC-DATC induced the activity of GR and GST, increased the hepatic GSH content and inhibited the rate of NDEA deethylation. The level of GSSG was decreased as a consequence of the increased activity of GR. These effects may contribute to possible antimutagenic and anticarcinogenic action of the dithiocarbamates investigated.

• Korean Journal of Environmental Agriculture
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• v.14 no.3
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• pp.329-337
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• 1995

The effect of N-(4-chlorophenyl) maleimide(CPMI), plant growth regulators, and alkylating agents on gluathione(GSH) content and glutathione S-transferase(GST) activity was examined with 3-day-old etiolated sorghum(Sorghum bicolor [L.] Moench) seedlings. The GSH content and GST activity of untreated seedlings were higher in shoots than that in roots. Response of GST activity in coleoptile was significantly greater than in other tissues of sorghum seedling. In CPMI-treated seedlings, GSH content was not significantly different from that in untreated seedlings. CPM treatment resulted in 2.3-fold increase in GST activity measured with metolachlor as substrate in the coleoptile region. In contrast, change in GST activity measured with metolachlor as substrate in the coleoptile region. In contrast, change in GST activity measured with 1-chloro-2, 4-dinitrobenzene did not occur. The increase of GST activity was caused by induction of a GST isozyme, which is substrate-specific to metolachlor. Subsequently, two hypotheses related to metolachlor detoxification were evaluated on the basis of regulation of plant growth regulators and substrate induction of GST activity. In coleoptile, GST activity measured with metolachior was increased to 2.1-and 3.4-fold by both 2, 4-dichlorophenoxyacetic acid(2,4-D) and metolachlor treated at the germination stage of sorghum, respectively. Treatments of 2.4-D and metolachlor also induced isozymes exhibiting the activity toward metolachlor. One of the isozymes was co-eluted with that induced by CPMI. These results indicated that increase in GST activity by CPMI may be partially related to auxin regulation and substrate induction.

• Biomedical Science Letters
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• v.26 no.3
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• pp.201-209
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• 2020

The effect of mulberry leaves and yacon tuber extracts (MYE) on antioxidant was tested in this study. The present study investigated the in vivo effects of the anti-oxidative effect of MYE on catalase (CAT), superoxide dismutase (SOD), glutathione S-transferase (GST), glutathione peroxidase (GSH-Px), and thiobarbituric acid reactive substances (TBARS). The seven-day acclimation of the mice was divided into six groups: Normal diet group (NOR), high fat diet group (HFD), high fat diet with 0.5% hydroxycitric acid group diet group for positive group (HHCA), high fat diet with 1% mulberry leaf and 1% yacon diet group (MYE-1), high fat diet with 3% mulberry leaf and 3% yacon group (MYE-3) and high fat diet with 5% mulberry leaf and 5% yacon group (MYE-5). The effect of serum antioxidant in the catalase of MYE-1, MYE-3, and HHCA comparing to HFD by 31.0%, 27.7% and 45.2%, respectively (P<0.05~0.01). The effect on hepatic antioxidant in the catalase of HFD was significantly increased 3.7 (77.3%) times than that of NOR (P<0.01). But, the activities of catalase were decreased significantly in MYE-1, MYE-3, MYE-5 and HHCA by 21.7%, 24.2%, 24.9%, and 28.8% compared to HFD, respectively. GSH-Px was significantly decreased in MYE-1, MYE-3, MYE-5 and HHCA by 15.5%, 37.1%, 23.4%, and 23.7% compared to HFD, respectively (P<0.05). The activities of CAT, SOD, GST, GSH-Px, and TBARS were more significantly decreased in MYE-1 and MYE-3 than those of HFD and HHCA. MYE have shown significant effects on anti-oxidative function against high fat diet.

• Journal of Life Science
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• v.9 no.6
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• pp.684-691
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• 1999

Gamdutang aqua-acupuncture solution (GAS), Gamdutang water-extracted solution (GWS) and Dae-Gamdutang aqua-acupuncture solution (DGAS) were prepared and tested for chemopreventive potentials. GAS was potent inducer of quinone reductase (QR) activity in Heapa1c1c7 murine hepatoma cells in culture, whereas GWS is less potent. GAS, GWS and DGAS were significantly induced QR activity in cultured rat normal liver cell, Ac2F. Glutathione (GSH) levels were increased about 1.8, 1.0 and 1.1 fold with GAS, GWS and DGAS in Hepa1c1c7 cells, respectively. In addition glutathione S-transferase (GST) activity was increased with GAS, GWS and DGAS. The effects of GAS, GWS and DGAS on the growth of Acanthamoeba castellanii were tested. Proliferation of A. castellanii was inhibited by GAS, GWS and DGAS at concentrations of 1 $\times$ and 5$\times$. These results suggest that GAS has chemopreventive potential by inducing QR and GST activities, increasing GSH levels and inhibition of polyamine metabolism.

• Journal of the East Asian Society of Dietary Life
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• v.11 no.4
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• pp.259-267
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• 2001

This study was to investigate the effect of selenium on hepatic antioxidative defense system and oxidative damage in lead-administered rats. Male Sprague-Dawley rats weighing 140$\pm$5g were divided into one normal group(Se, 0 ppm) and three lead groups according to dietary levels of selenium supplementation: Pb0(Se, 0 ppm), PbS(Se, 0.5 ppm), and PbSS(Se, 1.0 ppm). All experimental groups were fed the experimental diet ad libitum for 4 weeks, and lead groups fed one containing 2,000 ppm lead acetate. Liver superoxide dismutase(SOD) activities in Pb0 group increased compared with other experimental groups. Liver gluthathione peroxidase(GSH-px) activities in Pb0 group decreased compared with normal group, but those of PbS and PbSS groups significantly increased compared with Pb0 group. Glutathione S-transferase(GST) activities decreased in Pb0 group and not significantly different from PbS and PbSS groups compared with normal group. Reduced glutathione(GSH) contents and GSH/GSSG of liver in Pb0 group were lower than those of other groups. Liver vitamin E contents in Pb0 group were about 50% of the normal group, but those of PbSS and PbS increased more than Pb0 group. Liver damage in electron microphotography process decreased in RER, showed an increase in Iysosome and also an increase in swelling of mitochondria. and ordered as follows : PbSS. PbS. and Pb0. It was concluded that high levels of dietary selenium had protective effects on peroxidative damage of hepatic cell accompanied with increased antioxidative defense system in lead-administered rats.

• BMB Reports
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• v.31 no.4
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• pp.399-404
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• 1998

In order to gain further insight on the relationship between structure and function of glutathione S-transferase (GST), the six active-site mutants, R13T, K44T, Q51A, Q64A, S65A, and D98A, of human GST P1-1 were expressed in Escherichia coli and purified to electrophoretic homogeneity by affinity chromatography on immobilized GSH. The active-site mutants showed marked differences in substrate specificity. The substitution of Gln51 with threonine resulted in a drastic decrease in the specific activities to <10% of the wild-type value. The substitution of Arg13 with threonine resulted in more decreased specific activity toward cumene hydroperoxide and in the $I_{50}$ values of S-(2,4-dinitrophenyl) glutathione and benanstatin A. These results suggest that the substitution of Arg13 with threonine changes the conformation of the active site to increase the affinity for the product or electrophilic substrate. Lys44 seems to be in the vicinity of the H-site of hGST P1-1 or may contribute to some extents to the electrophile binding.

• Food Science and Biotechnology
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• v.16 no.3
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• pp.404-408
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• 2007

In this study, we investigated the effects by age of long-tenn supplementation of Epimedium koreanum Nakai (EKN)-containing water on the in vivo antioxidant capacities of rats. All rats were reared in a conventional system, and none of the rats showed any signs of aversion to the EKN solution. Neither the mean nor maximum life spans of the rats were extended by long-tenn administration of the solution. The EKN extract caused decreases in the levels of serum thiobarbituric acid reactive substances in the rats. The activities of superoxide dismutase, catalase, and glutathione (GSH) peroxidase within the liver cytosol decreased with age in both the control and EKN-supplemented groups. GSH peroxidase activity, however, was higher at old age in the EKN-supplemented group. The activities of GSH reductase and GSH-S-transferase, and the levels of free-sulfhydryl (SH) and total-SH group gradually decreased with age in both groups. However, there was some tendency for higher levels in the EKN supplemented group at a corresponding age. These results indicate that long-tenn supplementation of EKN water extracts alone does not exhibit discernible adverse effects in rats, and has some enhancing effects on the antioxidant capacities of the blood and liver, but it does not have life-prolonging effects.